Method of making digital photograph and digital photograph made by that method

ABSTRACT

A method of making a digital photograph composed of a moving water element and still element by applying a known computer image processing system, and a digital photograph made by this method, involves taking a basic photograph indicating a realistic image of still elements and photographs taken by applying a series of shutter speeds. A series of digital images corresponding to the above-mentioned photographs are indicated on a monitor of the processing system, and an image indicating a realistic image of the moving water element is selected from the series of digital images. A color matching operation is them applied to the selected digital image whereby a final digital image having a still element substantially color matched to that of the basic photograph and a realistic image of a moving water element is indicated on the monitor, and thereafter a realistic digital photograph is printed based upon the final image.

RELATED APPLICATIONS

This is a continuation-in-part of application Ser. No. 10/223,632, filedAug. 20, 2002 now U.S. Pat. No. 7,262,794, which claims priority toJapanese Application No. 2001-287825, filed Aug. 20, 2001.

BACKGROUND OF THE INVENTION

The present invention relates to a method of making a digital photographincluding the work of photographing a subject comprised of movingelements and still elements surrounding the same, in particular asubject including flowing water as a moving element, and improving thedigital photograph by a computer image processing technique.

In the long practiced art of taking silver film photographs, whenphotographing a subject comprised of moving elements including watersuch as a waterfall or rapids and still elements such as the scenerysurrounding them, as clear from the numerous photographs (clearlyindicating the photographic conditions) described in for example TakaoOtsuka, Utsukushiki Nihon no Kawa (Beautiful Rivers of Japan), takingthe photograph at the so-called “slow shutter speed” of 1/30 second etc.has been recommended as a condition for photographing such movingelements. The specifications for the recently popularized digitalcameras also follow this.

There is however still a doubt as to whether photographs taken by such atraditional photographic technique, leaving aside the aestheticevaluation, can be said to substantially match with the actual visualperception. The present inventor has long held doubts over photographyby this slow shutter speed in view of his experience in takingphotographs during studies of the dynamics of high speed rotatingobjects.

It is known that, in the case of photographing a subject comprising acore formed by a moving water element such as a waterfall or mountainstream and still elements such as trees surrounding the core, if a highshutter speed corresponding to the running speed of the core is appliedto take a photograph of such subject, the characteristic feature of themoving element can be captured as a photograph precisely, while thetotal image of the photograph becomes darker in comparison with thevisual recognition by a normal human being. Therefore, the darkness ofthe photograph of the above-mentioned subject obtained by the highshutter speed cannot generally be accepted, in spite of the effectiveresult indicating a realistic image of the moving element which isobtained by the application of the high shutter speed.

The applicant conceived that, if the above-mentioned problem due to thedarkness of photograph can be eliminated under the condition of keepingthe realistic image of the moving element, the photograph of the subjectcomprising the above-mentioned core and the still elements surroundingthe core can be accepted in the photographic society. This is the originof conceiving the present invention.

However, such changes in the darkness of a photograph are also affectedby such conditions of the setting diaphragm of lens, and ISO sensitivityof the film used (note: in the case of using a Digital camera, settingvalue of ISO Sensitivity). Therefore, before arriving at the presentinvention, the following basic research for confirming the influence ofthe shutter speed on the darkness of the photograph was carried out inconsideration of the influence of the “diaphragm condition”, “ISOsensitivity of film” used (note: in the case of using a digital camera,setting value of ISO Sensitivity), by four successive experiments.

[First Experiment]

To achieve the object of the present invention, the present inventorstudied what kind of shutter speed was suitable and whether photographyby the so-called “slow shutter speed” which had been recommended in thecase of photographing rapids, waterfalls, etc. was truly optimal fortaking a photograph of a realistic image (first experiment). That is, hetook photographs of the scene at the fountain plaza at the ImperialPalace Outer Garden (scene mainly of fountains) using a Nikon F-80camera and ASA100 film (Kodak E100SW), setting the exposure compensationto ±0 and the shutter speed divided into nine stages in the range of1/15 second to 1/4000 second (details shown in Table 1), and usingshutter priority AE. He then requested a local photo lab to develop thepositive film, read the obtained film by a scanner of a second computerimage processing system (owned by the present inventor), stored thedigital data in a computer (Macintosh G3), and made a comparative studyof the digital images displayed on the monitor. Further, the camera hadthe function of automatic adjustment of the diaphragm for maintainingsuitable exposure. For reference, the diaphragm values corresponding tothe shutter speeds are also shown in Table 1.

TABLE 1 FIG. No. S (seconds) V 1 1/15 *22  (+2) 2 1/30 *22  (+2) 3 1/6022 (+1) 4 1/125 22 5 1/250 16 6 1/500 11 7 1/1000  8 8 1/2000   5.6 91/4000   2.8 S: Shutter speed (seconds), V: diaphragm, *Suitableexposure compensation limit exceeded

TABLE 2 Equipment used First system Second system Computer Macintosh G4Macintosh G3 MO drive Olympus Servo MO 640C Same as first system ScannerMicrotec Scanmaster 4 Same as first system Printer Epson 2000 C Same asfirst system Monitor Mitsubishi Diamond RD21G Same as first system

Further, for convenience, when printing a digital image displayed on themonitor in the above-mentioned computer image processing system, ifusing a known color calibration technique, it is possible to easily makea digital photograph of color substantially matching the color(brightness, contrast, chroma, and color balance) of the digital image,so in the following explanation, the “digital image displayed on themonitor corresponding to the digital photograph of FIG. X” is expressedas the “digital image of FIG. X” for simplification of the explanation.

As clear from FIG. 1 to FIG. 9, when the shutter speed is extremely slow( 1/30 second or less), the contrast between the moving elements, thatis, the fountains, and the still elements (the surrounding trees etc.)falls and the fountains are captured in just the state of jets of water.As opposed to this, when the shutter speed becomes 1/60 second or more,the contrast between the moving elements and the still elements becomeshigher and even the drops of water of the fountains are clearlycaptured, it is found. Further, it was learned that this change isrelated nonlinearly with the change of the shutter speed, that is, thechange slows at a certain degree of speed or more (in this experiment,1/500 second). Further, it was confirmed that the slower the shutterspeed, the darker the photograph. When viewed visually, not just thestate of the jets of water, but the state of the presence of fallingdrops of water in the jets of water is perceived in reality, so it wasconfirmed that taking a photograph at the above slow shutter speed isnot in line with the object of the present invention. Note that it isself-evident that the same results are obtained even when using a cameranot having the function of automatic adjustment of the photographicconditions, if adjusting the diaphragm value and the shutter speed bymanual operation based on data clear from this experiment.

[Second Experiment]

Next, a commercially available digital camera (EOS D-30) was used totake photographs of the scene centered around the fountains in theImperial Palace Outer Garden in the same way as the above-mentionedphotographic experiment at an ISO sensitivity of 100 and shutter speedpriority changing the shutter speed to several stages (shutter speedsetc. shown in Table 3). The digital data obtained by this was stored inthe computer G4 of the first system shown in Table 2 from a CF card andthe digital images (FIG. 10 to FIG. 23) displayed on the monitor.

TABLE 3 FIG. No. S (seconds) V 10 1 *22 11 1/10 *22 12 1/20 *22 13 1/30*22 14 1/60 22 15 1/125 19 16 1/250 16 17 1/350 13 18 1/500 11 19 1/7509.5 20 1/1000 8 21 1/2000 4.5 22 1/3000 3.5 23 1/4000 *3.5 S: Shutterspeed (seconds), V: Diaphragm of lens, *Suitable exposure compensationlimit exceeded

In this experiment (second experiment), photographs were taken at aconstant exposure compensation condition (.0) and a shutter speed set toa shutter speed of 14 stages from 1 second to 1/4000 second. The digitalimages obtained by this photographic experiment were studied comparedwith each other by FIG. 10 to FIG. 23. As a result, it was confirmedthat the images almost completely matched the results of the abovesecond experiment using a silver film camera. Therefore, a detailedexplanation will be omitted. Further, since the camera had an automaticadjustment mechanism for automatically adjusting the diaphragm inaccordance with a change in the shutter speed to maintain a suitableexposure, the diaphragm values corresponding to the shutter speed arealso given in Table 3 for reference.

Both when using a silver film camera and when using a digital camera bythe above experiment, similar results are obtained, so in considerationof work efficiency, the above-mentioned digital camera was used in thefollowing photographic experiments.

[Third Experiment]

Further, the third experiment was conducted with the intention ofsupplementing the above experimental findings.

That is, in this photographic experiment, the ISO sensitivity was fixedto 100, the shutter speed was set to 1/500 second, and the exposurecompensation was adjusted to the five stages of −2, −1, ±0, +1, and +2to investigate the effects on the photograph quality. In the same way asthe above experiments, photographs were taken giving priority to theshutter speed (AE). The changes in the diaphragm value were recorded,whereupon only naturally the diaphragm was set as the exposurecompensation proceeded from the minus side to the plus side as 8, 5.6,4.0, and 3.5 These photographic conditions are shown in Table 4.

TABLE 4 FIG. No. E V 24 −2 8 25 −1 5.6 26 ±0 4.0 27 +1 3.5 +2 +3.5 S:Shutter speed (1/500 second), E: Exposure compensation, V: Diaphragm,*Suitable exposure compensation limit exceeded

The results of the comparison of the digital images (monitor display)obtained in this experiment show, as shown in FIG. 24 to FIG. 27, thatby moving the exposure compensation to the minus side, the contrastbecomes stronger at the details of the moving elements and the movingelements can be captured realistically as a result, but on the otherhand the digital image gradually becomes darker.

Note that with an exposure compensation of +2, the diaphragm of lensexceeds the minimum limit and the digital image also becomes too white,so this case was omitted from the series of attached drawings.

From the above experimental findings, it was confirmed that in order tophotograph in particular a subject comprised of moving elementsincluding flowing water and still elements and realistically captureeven details of the moving water elements, regardless of whether using asilver film camera or a digital camera, it is necessary to photograph itnot by the so-called “slow shutter speed”, but by a faster shutter speedand it was confirmed that taking the photograph darker is desirable.Note that it was learned that the suitable shutter speed corresponds tothe speed of change over time of the moving water elements from theexperimental findings of the later explained Embodiments 1 and 2.

According to the results of the above-mentioned experiments, it wasconfirmed that the dynamic feature of running water, such as a waterfall or mountain stream, can be correctly represented as a photograph,if the photograph is taken at a shutter speed corresponding speed of therunning water, although the entire photographic image becomes too darkso that the quality of the photograph cannot be accepted. Therefore, itis necessary to solve this problem.

In general, it is well known that the darkness of a photograph (digitalimage) can be easily corrected by applying a computer image processingtechnology which is disclosed in software such as Adobe Photoshop 5.5(Registered Trade Mark), that is, such correction of darkness can becarried out by a simple modification of darkness, or the modification ofdarkness in relation to contrast, and accordingly by the modification ofa tone curve. However, it is quite vague which type of correctionsmentioned would be suitable to correct the darkness of the photographcreated by applying a high shutter speed, and therefore, the followingfourth experiment was carried out to clarify this problem.

[Fourth Experiment]

The fourth experiment was conducted to throw light on this question.That is, as the original digital image of this experiment and thecomparative digital image to be used in the work, the digital images ofFIG. 15 and FIG. 22 were selected from the digital images obtained inthe above second experiment (for convenience, shown as FIG. 28 and FIG.19). Further, the darkness of the digital image of FIG. 29, that is, thephotograph taken at a shutter speed of 1/3000 second, was compared withthat of digital images (FIG. 30 to FIG. 36) obtained by simply adjustingthe brightness, adjusting a combination of the brightness and contrast,and adjusting the gradation, including adjusting the contrast forsafety's sake, with the objective of correcting them to the brightnessof the digital image (FIG. 28). As a result, it was confirmed that whilethe adjustment of just the brightness or the adjustment of just thecontrast is completely unsuitable, adjustment by the latter two can beadopted. Table 5 shows the relationship between the content of theadjustment work and the drawings.

TABLE 5 FIG. No. Content of image processing 28 Original image (same asFIG. 15) 29 Original image (same as FIG. 22) 30 Original image 29:Brightness adjustment (+35) 31 Original Image 30: Contrast adjustment(+25) 32 Original image 32: Brightness adjustment (+30) 33 Originalimage 32: Contrast adjustment (+19) 34 Original image 33: Brightnessadjustment (+50) 35 Original image 34: Contrast adjustment (+22) 36Original image 29: The brightness of the original digital Tone curveimage (input) and adjusted brightness (output) are shown in Table 8 asinput values and output values for each of the tone curves A, B, and Cof FIG. 62.

Note that the fact that similar results are obtained by combinedadjustment of the brightness and contrast and adjustment of thegradation can be understood from theoretical explanations relating tothe parameters for physical evaluation of images, for example, YoichiMitake, Dejitaru Karaa Gazo no Kaiseki-Hyoka (Analysis and Evaluation ofDigital Color Images) (page 91).

Here, when adopting the method of combined adjustment of the brightnessand contrast for adjustment of the brightness of a digital imagedisplayed on a monitor, the problem remains of what extent of adjustmentof the brightness to perform first. It was confirmed that this problemis solved by the technique of adjusting the brightness of the originalimage (FIG. 29) to close to the brightness of FIG. 28 by adjusting thebrightness, then adjusting the contrast to make the brightness of thedigital image as a whole closely match that of FIG. 28. This fact isproved by the fact that when comparing FIG. 31 and FIG. 33, thebrightness and contrast both substantially match.

Further, it was confirmed that it is possible to obtain similar resultsby adjusting the gradation by a known technique (adjustment of input andoutput of tone curve dialog box) (FIG. 36). For reference, the data ofgradation adjustment is shown in Table 8 with reference to FIG. 62.

Note that FIG. 62 shows a known tone curve added with data displaycoordinates A, B, and C for the purpose of explaining the detailedcontent of gradation adjustment.

From this series of experiments, the photographic conditions forpreparing a realistic digital photograph starting from a photographobtained by photographing moving elements including flowing water andstill elements and the technique for improving this digital photographto a realistic digital photograph by computer image processing becameclear. This is the crux of the present invention.

SUMMARY OF THE INVENTION

The present invention was developed based on the results obtained by theabove preliminary experiments. That is, the present invention has as itsbasic technical idea to photograph a subject comprised of a moving waterelement and still elements surrounding it, in particular a subjectincluding flowing water as a moving element, using a digital camera orsilver film camera at a high shutter speed corresponding to the speed ofchange over time of the moving water element, storing the takenphotograph as digital data in a computer of a computer image processingsystem (in the case of silver film photography, storing the image dataas digital data in the computer through the scanner of the computerimage processing system and, in the case of a photograph by a digitalcamera, storing the data in the computer directly or through a CF cardor other storage medium), correcting a digital image displayed on themonitor of the image processing system by simple adjustment of gradationor combined adjustment of brightness and contrast (first adjusting thebrightness and then adjusting the contrast) so as to obtain a realisticdigital image stressing in particular the moving water element, andthereby preparing a realistic digital photograph substantially matchingthe visual perception by this corrected digital image displayed on themonitor. Note that the above-mentioned “high shutter speed”, as clearfrom the explanation of the later examples, indicates a shutter speed ofat least 1/350.

It must be noted that the present invention based upon theabove-mentioned basic technical idea needs to overcome the practicalproblems such as how to confirm whether the digital photograph createdby the present invention can be accepted as substantially identical tothe visual image or not, or how to find a shutter speed that satisfiesthe requirement of the present invention. However, these problems can besolved practically, for example, the first mentioned problem is solvedpractically by using a photograph which is obtained by a standardshutter speed such as the automatically set shutter speed in the case ofphotographing based upon a programming mode, and the second mentionedproblem is solved practically by applying a series of several shutterspeeds which involves for example, an estimated flow speed of water, asindicated in the following explanation of the embodiments.

BRIEF EXPLANATION OF THE DRAWINGS

The patent or application file contains at least one drawing executed incolor. Copies of this patent or patent application publication withcolor drawings will be provided by the Office upon request and paymentof the necessary fee.

FIG. 1 is a digital photograph showing the results of an experiment ofphotographing as a subject a scene centered around fountains using asilver film camera at a shutter speed of 1/15 second (Example 1).

FIG. 2 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/30 second.

FIG. 3 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/60 second.

FIG. 4 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/125 second.

FIG. 5 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/250 second.

FIG. 6 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/500 second.

FIG. 7 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/1000 second.

FIG. 8 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/2000 second.

FIG. 9 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/4000 second(first experiment).

FIG. 10 is a digital photograph showing the results of an experiment ofphotographing the same subject as in FIG. 1 using a digital camera at ashutter speed of 1 second (second experiment).

FIG. 11 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/10 second (secondexperiment).

FIG. 12 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/20 second (secondexperiment).

FIG. 13 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/30 second (secondexperiment).

FIG. 14 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/60 second (secondexperiment).

FIG. 15 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/125 second(second experiment).

FIG. 16 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/250 second(second experiment).

FIG. 17 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/350 second(second experiment).

FIG. 18 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/500 second(second experiment).

FIG. 19 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/750 second(second experiment).

FIG. 20 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/1000 second(second experiment).

FIG. 21 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/2000 second(second experiment).

FIG. 22 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/3000 second(second experiment).

FIG. 23 is a digital photograph showing the results of an experiment ofphotographing the same subject at a shutter speed of 1/4000 second(second experiment).

FIG. 24 is a digital photograph showing the results of an experimentphotographing the same subject as in the first experiment using adigital camera, fixing the shutter speed to 1/500 second, and using anexposure compensation of −2 (third experiment).

FIG. 25 is a digital photograph showing the results of an experimentphotographing the same subject using an exposure compensation of −1(third experiment).

FIG. 26 is a digital photograph showing the results of an experimentphotographing the same subject using an exposure compensation of ±0(third experiment).

FIG. 27 is a digital photograph showing the results of an experimentphotographing the same subject using an exposure compensation of +1(third experiment).

FIG. 28 is a digital photograph showing an original digital image usedas a comparative subject in the third experiment.

FIG. 29 is a digital photograph showing an original digital image fordigital processing performed in the third experiment.

FIG. 30 is a digital photograph showing a digital image obtained byadjusting the brightness (+35) of the digital image of FIG. 29.

FIG. 31 is a digital photograph showing a digital image obtained byadjusting the contrast (+25) of the digital image of FIG. 30.

FIG. 32 is a digital photograph showing a digital image obtained byadjusting the brightness (+30) of the digital image of FIG. 29.

FIG. 33 is a digital photograph showing a digital image obtained byadjusting the contrast (+19) of the digital image of FIG. 32.

FIG. 34 is a digital photograph showing a digital image obtained byadjusting the brightness (+50) of the digital image of FIG. 33.

FIG. 35 is a digital photograph showing a digital image obtained byadjusting the contrast (+22) of the digital image of FIG. 34.

FIG. 36 is a digital photograph showing a digital image obtained byadjusting the gradation of the digital image of FIG. 29.

FIG. 37 is a digital photograph of the case of photographing as asubject a gully positioned immediately upstream of the Ryuzu Falls inNikko, Japan setting the shutter speed to 1/30 second in a series ofexperiments conducted using that subject.

FIG. 38 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/125 second.

FIG. 39 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/250 second.

FIG. 40 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/750 second.

FIG. 41 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/2000 second.

FIG. 42 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/4000 second.

FIG. 43 is a digital photograph obtained by image processing of a stillelement by computer image processing using FIG. 42 as an original imageso as to make it substantially match a standard photograph in color.

FIG. 44 is a digital photograph of the case of photographing as asubject the Yudaki Falls in Nikko, Japan setting the shutter speed to1/125 second in a series of experiments conducted using this subject.

FIG. 45 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/4000 second.

FIG. 46 is a digital photograph prepared by adjusting the brightness andgradation of the digital image of FIG. 45 as a whole.

FIG. 47 is a digital photograph prepared by processing a digital imagecorresponding to the digital photograph of FIG. 46.

FIG. 48 is a digital photograph obtained by copying a picture postcardof the Yudaki Falls sold at Nikko, Japan.

FIG. 49 is a digital photograph taken of waves breaking against theseawall at the Jogasaki seacoast using a shutter speed of 1/4000 secondand an exposure compensation of +2.

FIG. 50 is a digital photograph taken of the same subject using ashutter speed of 1/125 second and a standard exposure compensation of±0.

FIG. 51 is a digital photograph obtained by adjusting the digital imageof FIG. 49 in gradation to bring it close to the brightness of theseawall in FIG. 50.

FIG. 52 is a digital photograph when adjusting the contrast of FIG. 51to bring the brightness and contrast of the seawall close to the stateof FIG. 50.

FIG. 53 is a digital photograph prepared by clipping the seawall portionof FIG. 52 and pasting it over the corresponding portion of the digitalimage corresponding to the digital photograph 51.

FIG. 54 is a digital photograph prepared by adjusting the brightness(+55) of a digital image corresponding to the digital photograph FIG. 52and then adjusting the contrast (+8).

FIG. 55 is a digital photograph prepared by clipping the portion of thebreaking waves of FIG. 54 and pasting it over the corresponding portionof the digital image corresponding to the digital photograph (FIG. 52).

FIG. 56 is a digital photograph obtained by photographing of breakingwaves from the Pacific Ocean at the Kamogawa seashore setting theshutter speed to 1/125 second.

FIG. 57 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/800 second.

FIG. 58 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/1000 second.

FIG. 59 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/5000 second.

FIG. 60 is a digital photograph of the case of photographing the samesubject setting the shutter speed to 1/1600 second.

FIG. 61 is a digital photograph prepared by adjusting the brightness tocontrast of a digital image corresponding to FIG. 60 and furtheradjusting the rocky shoal portion by image processing.

FIG. 62 is a reference view showing data of adjustment of gradationperformed for adjusting the brightness and contrast of a digital imageperformed in the fourth experiment and Embodiments 1 and 2.

FIG. 63, FIG. 64, FIG. 65, FIG. 66, FIG. 67, FIG. 68 and FIG. 69 arereference drawings according to the Embodiment 5 showing the effects ofa change in the ISO sensitivity setting of the digital camera used.

FIG. 70 is a digital photograph of the case of photographing as asubject the ravine called TENJIN-KYO located in the central area ofHokkaido, Japan, setting the shutter speed to 1/125 sec.

FIG. 71 is a digital photograph of the same subject as FIG. 70 taken atthe shutter speed of 1/250 sec.

FIG. 72 is a digital photograph of the same subject as FIG. 70 taken atthe shutter speed of 1/350 sec.

FIG. 73 is a digital photograph of the same subject as FIG. 70 taken atthe shutter speed of 1/750 sec.

FIG. 74 is a digital photograph of the same subject as FIG. 70 taken atthe shutter speed of 1/1000 sec.

FIG. 75 is a digital photograph of the same subject as FIG. 70 made bythe present invention from the digital image displayed on the monitor ofa computer image processing system, corresponding to the digitalphotograph of FIG. 72.

FIG. 76 is a digital photograph of the same subject as FIG. 70 made bythe present invention from the digital image displayed on the monitor ofa computer image processing system, corresponding to the digitalphotograph of FIG. 71.

DESCRIPTION OF PREFERRED EMBODIMENTS

As already explained, in the experiments of the following embodiments,the experiments were conducted using as a camera for the photography theabove-mentioned digital camera (Canon D-30) (ISO sensitivity: 400)except for the experiment of Example 4 (using a Nikon Dlx) and using acomputer image processing system shown in Table 2, that is, a computerimage processing system comprised of a Macintosh G3 or G4 computer, anOlympus Servo MO 640C MO drive, and an Epson 2000C printer. Further, inthe experiments, the photographs were taken using a number of pixelsstored of 2160.times.1440, a compression ratio of about 1.3 MB, and aphotographic mode of shutter priority (Tv). In the case of Example 4,the photographs were taken using a FINE image mode and shutter prioritymode.

First Embodiment

In the experiment of this embodiment, a gully directly upstream of theRyuzu Falls in Nikko, Japan was selected as the subject. The Ryuzu Fallsis counted as one of the three famous waterfalls of the Nikko NationalPark along with the Kegon Falls and the Yudaki Falls. In particular, thescenery in the autumn is particularly widely known in Japan and overseasthrough magazines and picture postcards. However, with these scenicphotographs (picture postcards), it could be found that the majority ofthe water falling at the rapid speed is displayed in a state of whitestrips or far from the visual perception. Further, to achieve the objectof the present invention, the necessity for photographing the subject ata shutter speed corresponding to the condition found in the abovepreliminary experiments, that is, the speed of change over time of themoving water element, was confirmed.

First, the content of the experiments of this embodiment will beexplained with reference to Table 6 (showing photographic conditions)and FIG. 37 to FIG. 43

[Selection of Shutter Speed]: The technique was adopted of making use ofthe sophisticated functions of the digital camera used for thephotography, even though a compact camera, adopting the method ofselecting the shutter speed by interpolation (note: Sugaku Jiten(Mathematical Dictionary), 3rd edition, p. 387C, published by IwanamiShoten), performing the experiment while dividing the range from 1/30second to 1/4000 second into six stages as shown in Table 6, andselecting the digital image meeting the objective from the digitalimages obtained by this photographic experiment.

TABLE 6 FIG. No. S E V 37 1/30 +2 19 38 1/125 +0.5 22 39 1/250 ±0 19 401/750 ±0 9.5 41 1/2000 ±0 5.6 42 1/4000 ±0 4.5 43 Prepared by imageprocessing using FIG. 42 as original image S: Shutter speed, E: Exposurecompensation, V: Diaphragm value

[Photographic Results (Digital Image)]: As clear from the digitalphotographs (FIG. 37 to FIG. 42) corresponding to the shutter speeds, itwas learned that even when the shutter speed is the standard shutterspeed of 1/125 second, the rapids have considerable white strip-likeportions, the photograph as a whole gradually becomes dark along withthe rise in the shutter speed over that, but the difference in contrastat the details of the rapids becomes clear, but over a certain limit(specifically, over 1/750 second), the change-in contrast becomesslower. Comparing these digital photographs, the digital photograph ofFIG. 42 was selected as the digital image for image processing since itscontrast at details of the rapids was superior.

[Correction of Darkness]:

Based upon the knowledge obtained from the above-mentioned fourthexperiment, it was possible to create the brightness (light condition)of the digital image indicated on the monitor (corresponding to thedigital photograph FIG. 42) to a modified digital image of whichbrightness being substantially matching to the visual perception of thedigital photograph of FIG. 42, by three steps of gradual modification ofbrightness in relation to the contrast, while substantially maintainingthe contrast of the mountain stream (moving water element).Incidentally, the above-mentioned processing operation can beeffectively carried out by indicating the digital photograph of FIG. 38beside the digital image of the photograph FIG. 42 on the monitor.

Further, in this case as well, when there is a need to display a movingwater element more realistically, this problem is solved by performingthe above image processing while separating the moving water element andstill elements, processing to strongly hold the contrast particularly atthe details of the moving water element, and combining the imageprocessed moving water element and still elements by a known technique.

The problem remains, however, of how to select the comparative image.This problem has also been solved in practice as follows: That is, sinceit has been recognized from the past that a photograph taken at ashutter speed of around 1/125 second and a suitable diaphragmsubstantially matches the visual perception of the subject, a photograph(FIG. 38) obtained by photographing the subject under these photographicconditions was used as the comparative subject in this image processing.Note that this shutter speed has to be changed in accordance with theweather, light, and other photographic conditions and, in the case ofsilver film photography, the sensitivity of the film. Further, it is ofcourse possible to adopt as the above material for judgement aphotograph taken by a currently popular camera having an automaticexposure adjustment function, a photograph accepted as substantiallymatching the visual perception of large numbers of persons, picturepostcards, printed matter, etc.

The following image processing work was performed in accordance with theabove experimental conditions: That is, since the trees surrounding therapids in the above digital image (monitor display) of FIG. 42 areunnaturally dark compared with the corresponding portion of the digitalimage (FIG. 38) of the comparative image, the following image processingwas performed to correct the brightness of that portion. First, thatportion was selected and then adjusted in brightness (+27) and thencontrast (+10), the unnaturalness in the boundary between that portionand other portions was removed, and thereby the final digital imageshown in FIG. 43 was prepared.

Further, in the case of the above experiments (First and Secondexperiments), it was possible to take a photograph at a shutter speed of1/60 second in a state visually perceiving the fountains, but it becameclear in those experiments that this degree of shutter speed was tooslow and that it must be 1/250 second at the slowest. This fact showsthat “the shutter speed of photography required for producing arealistic digital photograph by photographing a subject comprised of amoving water element and still elements” has to be set corresponding tothe speed of the moving water element. Therefore, the photographictechnique of employing a plurality of shutter speeds obtained byinterpolation (plural shutter speeds, which involve a shutter speed Acorresponding to the estimated running or variation speed of the movingwater element and plural shutter speeds lower and higher than theabove-mentioned shutter speed A, are systematically applied) used in theexperiment of this example was confirmed to be practically valuable duein part to the effect of the superior operability of the camera used.

Second Embodiment

This embodiment is a photographic experiment of a scene including theYudaki Falls of Nikko, Japan after the experiment of Embodiment 1 on thesame day. In this experiment, the photographs were taken by selectingthe shutter speed by interpolation in the same way as the photographicexperiment of First embodiment. That is, the photographic experiment wasconducted giving priority to the shutter speed (AE) at shutter speeds offive stages from 1/30 second to 1/4000 second. The content of theexperiment is shown in Table 7.

TABLE 7 Shutter speed FIG. No. (sec) Diaphragm Exposure compensation1/30 19 +2 FIG. 44 1/125 22 +0.5 1/250 19 ±0 1/750 9 ±0 FIG. 45 1/400016 ±0

The inventor stored the digital data obtained by this in the computer G4of the above computer image processing system 1 from a CF card,displayed the digital images on the monitor, and compared the digitalimages of the monitor display, whereby he judged that a shutter speed of1/4000 second (FIG. 45) showed the Yudaki Falls well. The rapidsportion, however, was darker than the digital image photographed at ashutter speed of 1/125 second (FIG. 44), so the brightness of thedigital image (FIG. 45) as a whole was adjusted by adjustment of thegradation (Table 8) to prepare another digital image (FIG. 46). Sincethe tree portion occupying the portion left of the rapids was stilldarker than the above digital image (FIG. 44), the corresponding portionof the digital image (FIG. 44) was clipped by a known technique andpasted on the corresponding portion of the digital image (FIG. 46). As aresult, it was possible to display the desired digital image (FIG. 47)on the monitor.

Further, for reference, a copy of a picture postcard (Yudaki Falls)commercially sold at Nikko is shown in FIG. 48.

Third Embodiment

This embodiment shows the results of an experiment of photographing ascene including waves breaking against the seawall at Jogasaki in Izu,Japan.

In the case of this subject, the waves breaking against the seawallstrike the seawall and break apart at substantially constant intervals.The waves themselves deform at a considerably fast speed, so to capturethem realistically, it is necessary to set the shutter speed at a highspeed. Therefore, based on the discoveries obtained in Examples 1 and 2,a photographic experiment was conducted at the four stages of shutterspeeds of 1/125, 1/250, 1/500, and 1/4000 second. As a result, it waslearned that the photographic result when making the shutter speed4000/sec. and making the exposure compensation +2 (FIG. 49) expressedthe waves most realistically. On the other hand, it was confirmed thatthe seawall which the waves struck was extremely dark compared with thedigital image (FIG. 50) obtained by photography under the standardphotographic conditions (shutter speed of 1/125 second, exposurecompensation ±0).

Therefore, the darkness of the digital image (FIG. 49) was adjusted (byadjustment of gradation), the brightness of the seawall in particularwas corrected to a state close to the digital image (FIG. 50), and thecorrected digital image (FIG. 51) was displayed on the monitor (seeTable 8 for content of gradation adjustment). The content of thisgradation adjustment is shown in Table 8. If compared with the seawallof the digital image (FIG. 50), however, it was learned that thecontrast between detailed elements of the seawall portion was weak, sothe digital image (FIG. 51) was adjusted in brightness (+37) andcontrast (+50) in that order and the resultant digital image (FIG. 52)displayed on the monitor. Next, the seawall portion of the digital image(FIG. 52) was clipped and pasted over the corresponding portion of thedigital image (FIG. 51), and the difference at the boundary portion ofthe pasted seawall portion and the original portion of the digital image(FIG. 51) was removed by a known technique to prepare the desireddigital image (FIG. 53).

TABLE 8 Input values (birhgtness of original digital images) and outputvalues (adjusted brightness) of points A, B, and C shown in FIG. 62(tone curves) Point A Point B Point C Input Output Input Output InputOutput FIG. No. value value value value value value FIG. 36 64 36 128 79192 143 FIG. 46 64 47 128 102 192 170 FIG. 51 64 18 128 38 192 83

In addition to the above image processing, it is possible to produce adesired digital image by the following technique. It is possible tofirst use the above digital image processing to display a digital image(FIG. 52) on the monitor, then adjust the brightness of the digitalimage (FIG. 49) to make it brighter (+55), then adjust the contrast (+8)to thereby display another digital image (FIG. 54) on the monitor, clipthe portion of the waves of the digital image (FIG. 54) and paste itover the corresponding portion of the digital image (FIG. 52), thenremove the difference of the boundary portion between the pasted waveportion and the original portion of the digital image (FIG. 52) by aknown technique (for example, using a stamp tool) to display the desireddigital image (FIG. 55) on the monitor.

The digital image processing work in the above mentioned embodimentsincludes storing the digital data of the digital image displayed on themonitor of the image processing system 1 in an MO disk by an MO drive,using this MO disk to store the data in the computer G3 through the MOdrive of the image processing system 2, displaying the data as a digitalimage (FIG. 50) on the monitor of the system, and performing theabove-mentioned image processing work and printing work on the digitalimage. Further, the change in color occurring when transferring digitaldata from the image processing system 1 to the image processing system 2is of course corrected by a known calibration technique.

Fourth Embodiment

This embodiment is an experiment of photographing rough waves of thePacific Ocean breaking against the seashore at Kamogawa, Boso, Japanunder the following conditions using a Nikon Dix (ISO sensitivity: 400):

That is, the shutter speed was set to 11 stages of shutter speeds in therange of 1/30 second to 1/16000 second ( 1/16000, 1/10000, 1/8000,1/5000, 1/3200, 1/1000, 1/800, 1/200, 1/125, 1/60, and 1/30 seconds) andthe photographs taken by priority to shutter speed. Note that as clearfrom the description in the specifications of this camera, when theshutter speed is from 1/6000 second to 1/30 second, the diaphragm isautomatically adjusted and the photo taken at the suitable exposure, sothe photographs were taken with this function in mind.

In the same way as the experiments of Embodiments 1 to 3, digital datawas stored in the computer G4 of the image processing system 1 from a CFcard and stored by an MO drive into an MO disk and then the computer G3of the digital image processing system 2. The comparative study of thedigital images displayed on the monitor gave similar experimentalresults as in Embodiments 1 to 3. To avoid duplication in explanation,the results obtained in particular in this experiment will be explainedwith reference to the digital photographs taken at shutter speeds of1/125 second, 1/800 second, 1/1000 second, 1/5000 second, and 1/16000second. Further, when the shutter speed exceeds a certain limit,specifically 1/6000 second, the photographed image as a whole becomesextremely dark. With this as it is, the image is unsuitable as material,so known computer image processing is used to correct the brightness (byadjustment of the brightness and then contrast) to produce the digitalimages (FIG. 56, FIG. 57, FIG. 58, FIG. 59, and FIG. 60) and use theseas materials for studying the experimental results.

As already explained (for example, explanation of Embodiment 1), ifmaking the shutter speed one corresponding to the speed of change overtime of the moving water element, the photograph as a whole becomesdark, but the contrast of the details comprising the moving waterelement becomes stronger. It is learned that this tendency becomes lessthe further higher the shutter speed. This fact was confirmed by theexperiment of this example as well. That is, if the shutter speedexceeds 1/6000 second, the limit of suitable white valance is exceededand the digital photograph as a whole becomes particularly dark, but ifthe shutter speed becomes 1/16000, it was possible to display on themonitor a digital image realistically capturing the dynamic wavesstriking and breaking apart at the shoals. Therefore, the digital imagewas processed to adjust its brightness (+30) and then contrast (+50) andthe digital image of FIG. 60 was displayed on the monitor.

The shoals at the center of this digital image (FIG. 60), however, aredarker than the waves and uniformly blacked out, so the shoal portion ofthe digital image obtained by photographing the scene at a shutter speedof 1/125 second was clipped and pasted over the corresponding portion ofthe digital image (FIG. 60), then the sky portion was selected andcorrected to make it brighter by a known technique (brightness +12), thetrimming was changed, and further the aspect ratio of the image waschanged to be able to produce the digital image shown in FIG. 61.Further, it was possible to produce a digital image having color uniqueto the inventor (brightness, contrast, chroma, and color balance) byadjusting the chroma of the digital image of FIG. 61 and the colorbalance between elements forming the image.

From the above results, it was learned also that except when producing adigital image particularly stressing the waves striking and breakingapart at the shoals (FIG. 61), it is possible to take a sufficientlyrealistic digital photograph of waves even at 1/500 second and that whentaking a photograph stressing the waves striking and breaking apart atthe shoals, trouble and time are taken for post processing (computerimage processing) to obtain a photograph realistically showing thecontrast over the details of that portion, but taking the photo at ashutter speed of 1/16000 is desirable. However, the brightness of thesky portion and shoal portion has to be digitally processed to furthercorrect it to a state close to the digital image taken under standardphotographic conditions (shutter speed of 1/125 second).

From this result, it was confirmed again that, leaving aside specialcases where it is intended to particularly stress rhythmical wavesstriking and breaking apart at the shoals, the desired realistic digitalphotograph can be taken by selecting a shutter speed corresponding tothe speed of change over time of the moving waves, that is, at theslowest 1/500 second.

Above, the basic technical idea of the present invention wasspecifically clarified by the explanation of Embodiments 1 to 4. It wasconfirmed from the experiments of these embodiments that, if the shutterspeed is made high, inevitably the photographic result changes to one ofinsufficient exposure and that the darker the photographic image, themore trouble is taken for the computer image processing. On the otherhand, along with the rapid spread of and advances in digitalphotographs, the functions of digital cameras have greatly progressed inthese past few years. Since photographic equipment enabling not only theshutter speed, but even the ISO sensitivity to be set to 1600, such asthe Canon D30, Canon E-1, and other digital cameras used in the aboveexperimental examples are being sold commercially, so the inventorconducted the following photographic experiment and conducted thefollowing test of computer image processing of a digital image obtainedby this photographing as the original image for the purpose ofinvestigating the effect of increasing the ISO sensitivity of thedigital camera.

Fifth Embodiment

This embodiment shows the results when using as an original photograph adigital photograph taken of the Oirase Stream of the Towada NationalPark (turbulent flow) using the above-mentioned Canon D30 digital cameraat three levels of ISO sensitivity of 400, 800, and 1600 and progressiveshutter speeds of 1/125 second to 1/2000 second.

Next, to avoid overlap in explanation, the explanation will be givenfocusing on the problems while referring to Table 9 and FIG. 63 to FIG.69.

TABLE 9 Shutter speed Exposure FIG. No. ISO (sec) Diaphragm compensationRemarks 63 400 1/125 8.0 −1 64 400 1/500 4.0 −1 65 FIG. 63 colorcorrected 66 800 1/500 4.0 ±0 67 800 1/125 6.7 ±0 68 800   1/1000 4.0 −169 FIG. 67 color corrected

Note: In the shutter priority photography, the shutter speed andexposure compensations were changed, but the diaphragm was automaticallyadjusted and is entered here for reference.

(1) The faster the shutter speed, only naturally, the darker thephotographic image. However, since the ISO sensitivity was set high, thedarkness of the photographic image became lighter in compared with thelower setting of ISO sensitivity, further, the change in the darkness ofthe photographic image became weaker. In the case of FIG. 66, resultsextremely close to the visual perception are obtained. However, it wasnecessary to finely correct the color balance between the trees of stillelements forming the photographic image and the flowing water by imageprocessing.

(2) As mentioned above, if ISO sensitivity is set high, the qualityproblem of the photographic image due to the darkness is mitigated incompared with the case of setting ISO sensitivity lower. On the otherhand, since another problem due to the possible damage to thephotographic image of the water stream by halation must be prevented, itis required to carefully select the high ISO sensitivity in the relationto the shutter speed together with the exposure compensation.

(3) Further, even when the original photograph differs from the case ofFIG. 66 (FIG. 64, FIG. 68), as clear from Embodiments 1 to 4, it wasconfirmed that it is possible to correct it to a digital image (FIG. 64and FIG. 68) being similar to FIG. 66, by computer image processing(FIG. 64 and FIG. 68).

(4) When using FIG. 66 (ISO sensitivity of 800, shutter speed of 1/500second) as the original photograph, the image processing makes fineradjustments compared with other cases, so the shutter speed ispreferably set high. Note that in a photographic experiment using an ISOsensitivity of 1600, the exposure correction value is set excessively toone side, so the color level of the photographic image as a wholebecomes extremely dark in level, excess time is required for thecomputer image processing, and in extreme cases the limits of imageprocessing are exceeded. Fortunately, with digital cameras now on themarket, the digital image can be visually checked on the monitor screenof the camera even right after being taken, so this sort of failure canbe avoided by such a check. Therefore, in practice, it is clear that itis preferable to first take a preliminary photograph under standardphotographic conditions such as program photograph, confirm by themonitor screen of the camera the ISO sensitivity of an extent where nohalation occurs in the flowing water and other moving elements making upthe digital image in relation with the speed of flow of the flowingwater, then select the ISO sensitivity and, while in relation with thespeed of flow of the flowing water as well, take the photograph at ahigh shutter speed of at least 1/350 second.

From the above-mentioned explanation relying upon the preliminaryExperiments 1-4 and the experiments disclosed in the embodiments 1-5, itwas confirmed that so-called high shutter speed corresponding to thevariation speed (or velocity) of the moving water element is the key tomaking a digital photograph as a realistic photographic image, insteadof the traditional slow shutter speed.

However, even if the shutter speed is set appropriately, it is stillimpossible to avoid the influence of the ISO sensitivity of the filmused in the case of using a digital camera, the setting value of ISOsensitivity, diaphragm of lens, exposure compensation, weatherconditions of the photographing location. However, it was confirmedthat, if plural shutter speeds are selected by interpolation (see theexplanation of Embodiment 1) under the consideration of theabove-mentioned additional factors, and the most realistic photographicimage is selected from the photographic images obtained by theabove-mentioned photographing, it is possible to make a realisticdigital photographic image, which can be accepted as a visual image, bymodifying the brightness and contrast, or gradation by using the knowncomputer image processing technology.

Further, the work for making the brightness of the digital imagedisplayed on the monitor substantially match with the visual perceptionis only naturally affected by the subjectivity of the operator engagedin the image processing work. When it comes to the brightness of theimage, as clear from the explanation of the fourth experiment and theseries of embodiments, this is an issue involving the brightness andcontrast. Along with other color elements (color balance), while adifference of degree, it is not possible to ignore the fact that thereare individual differences in its perception. The vast majority ofpeople, however, share a common perception within a certain range offluctuation, so the range where the brightness and contrast of digitalimages being compared can be judged the same by the visual perception ofthe vast majority of people, not including specific persons such aspersons judged medically color blind, is defined as “substantiallymatching with the visual perception”.

Sixth Embodiment

This embodiment indicates the result obtained from the followingexperiment of the present invention applied to photographing thebeautiful ravine called TENJIN-KYO, located in the central area ofHokkaido, Japan. In this experiment, a series of digital photographswere taken using a Canon D30® digital camera by applying “shutterpriority mode” under the following conditions indicated in Table 10, andthereafter computer image processing operations were carried out asexplained later.

TABLE 10 Shutter speed in fractions of a second 1/125, 1/250, 1/350,1/750, 1/1000 Exposure compensation value  ±0 ISO Sensitivity 200

The digital photographs taken as described above are indicated in FIG.70, FIG. 71, FIG. 72, FIG. 73, FIG. 74, and the digital photographsfinally obtained by the present invention characterized by claim 4 areindicated in FIG. 75 and FIG. 76.

According to this experiment, it was found that the digital photographof FIG. 70 cannot be accepted as a realistic digital photograph of thesubject, because a water stream indicated in this photograph is affectedby remarkable halation whereby the beauty of the subject is completelyspoiled, in spite of indicating a realistic view of still elementssurrounding the water stream, such as trees, rocks, etc.

On the other hand, it was confirmed that the digital photograph of FIGS.71-74 indicate a dynamic flowing condition of the water stream, in spiteof the fact that the still elements such as trees, rocks, etc. areindicated in a dark condition which cannot be accepted as a realisticimage. It was also confirmed that the above-mentioned dark condition ofstill elements becomes more remarkable as the shutter speed isshortened.

In the above-mentioned condition of the digital photographs of FIGS.71-74, the digital photograph of FIG. 72 taken at a shutter speed of1/350 sec. can be selected as the most pertinent material to make adigital photograph indicating a realistic image of a water stream,because the water stream of the digital image indicates the mostrealistic image thereof. Therefore, the following computer imageprocessing operation was applied to the digital image P₁ indicated onthe monitor of the computer image processing system, based upon thedigital photograph of FIG. 72, by applying a known color adjustmentoperation disclosed in the user's guide of Adobe Photoshop 4.0, chapter6 and chapter 7 (Japanese edition).

Since the color modifying operation applied to the sixth embodiment canbe understood as a “high level technique” in the field of known colormodifying operation, this operation applied to the sixth embodiment isexplained in detail, as follows.

As a first step operation, the entire area of still elements of digitalimage P₁ is selected in the condition that the water stream portion isexcluded. This operation is carried out by firstly selecting the menuitem “range of selection” and then selecting the menu item “colormodification area” included in the pull down menu, then selecting anarea of the static elements at a point marked “X” in the digital imageP₁ indicated on the monitor of the computer image processing system asindicated in FIG. 72. According to the above operation, a small blackand white representation of the image is indicated on the monitor. Inthis image, a data indication system for confirming the desired range ofcolor modification is indicated, whereby the entire area of the desiredrange of color modification operations can be adjusted and the desiredarea for color matching operation can be confirmed by being outlined bya flickering dotted line surrounding the selected area, while on theother hand, the other area of the digital image which is protected fromthe color matching operation is indicated in a condition without beingsurrounded by the above-mentioned flickering dotted line.

Under the above-mentioned condition, the data indication signal systemis operated to confirm the setting condition that the desired colormatching operation can be carried out.

As the second step operation, the “Edit” menu is firstly selected fromthe main menu, then “Copy” is selected in the pull down menu.Thereafter, the item “layer paste” is selected in the “Edit” menu,whereby a digital image P₂ having a view identical to the digital imageP₁ is indicated on the monitor of the system under the condition thatthe entire area of static elements can be subjected to colormodification operation, while the other area of the digital image, thatis, the area of the water stream does not substantially change from itsrealistic condition.

Then, a color matching operation is applied to the digital image P₂ tomodify the color of the entire area of the static elements to create acondition in which the color of this entire area of the static elementsis color matched to the color of the entire area of the static elementsof the digital image P₁ corresponding to the photograph indicated inFIG. 70, while maintaining the realistic color condition of the waterstream as indicated in the digital image P₁ corresponding to the digitalphotograph of FIG. 72. In other words, a digital image P₃ having arealistic image of the water stream and the entire area of the staticelements is indicated on the monitor of the computer image processingsystem.

However, it must be recognized that the above-mentioned color matcheddigital image P₃ is composed of two components, that is a first layerformed by an entire area of the static elements to which the colormatching operation is applied, and a back layer of the photographicsubject, that is the original digital image P₁ indicated on the monitorof the system. Accordingly, it is necessary to integrate theabove-mentioned two layers into one layer for printing. Therefore, asthe next step operation, the above-mentioned two digital images of twolayers are integrated to form a single layer, whereby a digital image P₄composed of the realistic image of the water stream and beingsubstantially color matched to the digital photograph indicated in FIG.72, and the entire area of the static elements modified in color tomatch the digital photograph of FIG. 70, are integrated to form thedigital image P₄, indicated on the monitor of the computer imageprocessing system.

After completing the above-mentioned operation, the printed digitalphotograph indicated as FIG. 75 being substantially identical to thedigital image P₄, was printed.

The following additional experiment was also performed. That is, sincethe contrast of the water stream of the ravine indicated in the digitalphotograph (FIG. 71) is weak from the view condition, the contrast ofthis portion of the digital image indicated on the monitor of the systemis increased to a slightly stronger condition (+5) so that a digitalimage Q₁, which can be accepted as a digital image similar to thedigital image P₁, can be indicated on the monitor of the computer imageprocessing system used for the above-mentioned sixth experiment, and acolor modification operation similar to the operation of the sixthexperiment was applied to the digital image Q₁ to indicate a digitalimage Q₂ having a color substantially identical to the color of thedigital image P₄, and therefore, the substantially identical result tothat of the above mentioned experiment was obtained as indicated in FIG.76.

While in the above mentioned sixth embodiment, additional colormodification was applied to the final digital image P₄, indicated on themonitor of the computer image processing system to slightly change apart of the final digital image indicated on the monitor of the system,such a slight color modification can be accepted as a matter that shouldnot deny the beneficial effect of the present invention.

It was confirmed that the above-mentioned color matching operationexplained as the sixth embodiment can be carried out by the improvedsystem based upon the software of Adobe Photoshop CS2, whereby thecomplicated operation such as “selection of layer paste”, and“integration of two layers” are omitted.

EFFECTS OF THE INVENTION

In the explanation related to the sixth embodiment, a very effectivemethod of color modification applied to the still elements is explained.It is normal that a mountain stream and waterfall usually include rocksand stones within the entire area thereof, and therefore the followingmethod for selecting still elements as the target of color modificationis also practically useful.

As the first step operation, the moving water element is provisionallyselected by specifying a pure water portion based upon the colorthereof, in the same condition, that is, black and white dots areindicated in the provisionally selected portion (not the target of colormodification) of the moving water element on the monitor. In thiscondition, a popup window to adjust the provisionally selected area(element) for color modification is indicated on the monitor, wherebythe entire area of range of provisional color modification can beadjusted by operating the popup window. After the operator confirms theprovisionally selected area for color modification, the “OK” button inthe popup window is clicked, and the popup window is dismissed.

As the second step operation, in the pull down menu “Select,” the item“Inverse” is specified whereby the desired area of the still elements isselected for the color modification operation. Thereafter, the identicalmethod applied to the sixth embodiment for indicating the digital imagecomposed of above-mentioned selected still elements (first layer) andback layer on the monitor, is operated. In other words, a colormodification operation can be applied to the above-mentioned selectedarea of the still elements (first layer).

Since the successive operation after the above-mentioned selection ofthe desired area of still elements for a color modification operation isidentical to the corresponding operations of the sixth embodiments, theexplanation of these successive operations is omitted.

1. A method of making a digital photograph of a subject composed of amoving water element and still elements surrounding said moving waterelement provided with a color condition (brightness, contrast, chromaand color balance) substantially matched to a naked eye view of saidsubject, comprising: a first step operation of taking a photograph at astandard shutter speed in a range between 1/60 and 1/125 seconds,whereby said photograph is composed of still elements indicated in acolor matched condition to said naked eye view, a second step operationof taking a series of photographs of said subject by applying a seriesof shutter speeds including a shutter speed identical to an estimatedmoving speed of said moving water element, said photographs then beingdisplayed as respective digital images on a monitor of a computer imageprocessing system, a third step operation of selecting one of saiddigital images based upon a color condition of said moving water elementbeing substantially identical to said naked eye view thereof from saidseries of digital images indicated on said monitor in said second stepoperation, a fourth step operation of indicating a digital image basedupon said digital image selected in said third step operation composedof a first layer and a back layer, the first layer indicating stillelements to which color modification is applied in an overlappedcondition to the back layer indicating said digital image selected insaid third step operation, a fifth step of operation of applying a colormodification to said first layer of said digital image indicated in saidfourth step operation, for making said first layer substantially matchedto a corresponding portion of said photographic image obtained in saidfirst step operation, a sixth step operation to combine said first layeron which said color modification operation of said fifth step operationis completed and said digital image of said back layer in overlappedcondition, whereby a material digital image for printing is made, and aseventh step operation to print said material digital image.
 2. Themethod of claim 1, wherein said fourth step operation is carried out bydirectly specifying still elements to which color modification is to beapplied.
 3. The method of claim 1, wherein said fourth step operation iscarried out in such condition that firstly, said moving water element isprovisionally selected by specifying a color of said moving waterelement, secondly said still elements of said digital image arespecified by inverting said provisionally selected portion of saiddigital image, and thereafter a digital image composed of a first layerindicating said specified still elements and said back layer isindicated on said monitor.